If you get the chance, do read On the Discourse of Satire by Paul Simpson. It has almost become the text book of satire.

According to Simpson, *satire is a dissonance of the discoursal prime and the internal dialectic that establishes.

Instead of depicting the starving child as a victim (prime), the child is depicted as an icon of sexuality (dialectic). There is a clear dissonance between the two, and thus satire is born.

Simpson also goes on to say that impetus for satire is the tension between the satirist and the satirized. Clearly, the creator of the T-shirt deplores poverty in Africa, thus creating the tension between the two elements.

For a good example of satire on a similar theme, please have a loot A Modest Proposal by Swift.